Rounding to the nearest 10
What is 23 rounded to the nearest 10? Explain your thinking!
23 rounded to the nearest 10 is 20 because according to the 5 and over rule, any number smaller than 5 in the ones place means that we will round down. 23 is also closer to 20 than it is to 30.
What is 178 rounded to the nearest 100? Explain your thinking!
178 rounded to the nearest 100 is 200 because according to the 5 and over rule, any number smaller than 5 in the tens place means that we will round up. 178 is also closer to 200 than it is to 100.
Round to the nearest 10 to estimate: 138 + 435 = ?
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140 + 440 = 580
Use mental math to add, show your work!
136 + 43 = ?
136 = 100 + 30 + 6
43 = 40 + 3
100 + 40 = 140
140 + 30 = 170
170 + 6 = 176
What is 54 rounded to the nearest 10? Explain your thinking!
54 rounded to the nearest 10 is 50 because according to the 5 and over rule, any number smaller than 5 in the ones place means that we will round down. 54 is also closer to 50 than it is to 60.
What is 428 rounded to the nearest 100? Explain your thinking!
428 rounded to the nearest 100 is 400 because according to the 5 and over rule, any number smaller than 5 in the tens place means that we will round up. 428 is also closer to 400 than it is to 500.
Round to the nearest 100 to estimate: 198 + 426= ?
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200 + 400 = 600
Ue mental math to add, show your work:
218 + 274
218 = 200 + 10 + 8
274 = 200 + 70 + 4
200 + 200 = 400
10 + 70 = 80
8 + 4 = 12
400 + 80 + 12 = 492
What is 85 rounded to the nearest 10? Explain your thinking!
85 rounded to the nearest 10 is 90 because according to the 5 and over rule, if the number in the ones place is 5 and above we that we will round up.
893 rounded to the nearest 100 is 900 because according to the 5 and over rule, any number smaller than 5 in the tens place means that we will round up. 893 is also closer to 900 than it is to 800.
Round to the nearest 10 to estimate: 644 + 172= ?
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640 + 170 = 810
Use mental math to add, show your work:
325 + 437 = ?
325 = 300 + 20 + 5
437 = 400 + 30 + 7
300 + 400 = 700
20 + 30 = 50
7 + 5 = 12
700 + 50 + 12 = 762
What is 67 rounded to the nearest 10? Explain your thinking!
67 rounded to the nearest 10 is 70 because according to the 5 and over rule, any number in the ones place that is 5 and above means that we will round up. 67 is also closer to 70 than it is to 60.
What is 547 rounded to the nearest 100? Explain your thinking!
547 rounded to the nearest 100 is 500 because according to the 5 and over rule, any number smaller than 5 in the tens place means that we will round up. 547 is also closer to 500 than it is to 600.
Round to the nearest 100 to estimate: 175 + 126 = ?
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200 + 100 = 300
Use mental math to add, show your work:
103 + 541 = ?
103 = 100 + 3
541 = 500 + 40 + 1
100 + 500 = 600
600 + 40 = 640
640 + 1 = 641
Round 44 to the nearest 10. Explain your thinking!
44 rounded to the nearest 10 is 40 because according to the 5 and over rule, any number smaller than 5 means that we will round down. 44 is also closer to 40 than it is to 50.
What is 635 rounded to the nearest 100? Explain your thinking!
635 rounded to the nearest 100 is 600 because according to the 5 and over rule, any number smaller than 5 in the tens place means that we will round up. 635 is also closer to 600 than it is to 700.
Round to the nearest 10 to estimate: 644 + 172 = ?
Show your work!
640 + 170 = 810
675 + 237 = ?
675 = 600 + 70 + 5
237 = 200 + 30 + 7
600 + 200 = 800
70 + 30 = 100
5 + 7 = 12
800 + 100 + 12 = 912